steering wheel shakes when i hit bumps??

[mikesmith]

hey guys

got a mq swb which is sprung over. it had 33's on it to start with and it drove perfect now i went to 35's (micky t claws) when i first put them on i hit a bump and the steering wheel went to violent shakes. it did it when i was going slow.

it still does it a bit now not as bad but why would it do it??

i have tightened the wheel bearings and it has a brand new rtc steering dampner.

cant work out why, putting 38's on soon and dont want the wheel shaking with them on.

[Brandon1989]

my mate had the same kind of problem when he had his old bridgestones on. He did the same thing and replaced the steering dampner but didnt help. they were a 33X12.5 and had a real flat tread, we then put on the federals that i have in a 265/75r16. Rolling diameter they are the same but the are a little skinnier, and are basically 4 chunks of tread.

dont know if that will solve your problem, but it seemed to solve ours

[patrolpaul]

Try your panhard bushes. They might not look stuffed but they are the usual problem. There is heaps on here about this type of problem. Do a search and it should answer your question. With the bigger tires the add load to the rubbers which causes the front diff to move side to side. Worked for me!

[bru21]

no panhard on a leaf truck. I would check your tyre pressure is not too high. The bigger the tyre the lower the pressure. I drove my 35's on 22 front 18 rear on a gq ute, any higher and it sucked. I seem to get away with it on the 37's running higher pressures now - but my front end is very ridgid, factory castor, fox dampner etc

[j-top paj]

no panhard on a leaf truck. I would check your tyre pressure is not too high. The bigger the tyre the lower the pressure. I drove my 35's on 22 front 18 rear on a gq ute, any higher and it sucked. I seem to get away with it on the 37's running higher pressures now - but my front end is very ridgid, factory castor, fox dampner etc

22psi on road?
i drop to 18 offroad and i have it when i drive onroad to a servo or whatever. it feels too heavy.
i run 38 cold in mine

[David_S]

This is a not uncommon problem with MQs. I have had it at least 3 times on my old MQ at roughly 6-7 year intervals. It's pretty disconcerting when you get the shakes I have to admit.

It is generally due to cumulative wear in all the various steering components particularly balljoints. Your moving to larger tyres probably just exposed an underlying problem which would have surfaced in due course. The springover probably does not help either. Another common cause in early MQs particularly is wear in the front spring bushes. They had steel bushes which wore the steel pins rather than the bushes.

On another thread

http://outerlimits4x4.com/viewtopic.php ... highlight=

I listed the most common causes of the "shakes" (in no particular order) as:

1) Worn knuckle flange swivel bearings or incorrectly adjusted bearings
2) Wheels out of balance
3) Steering damper shot
4) Worn shock or shocks
5) Track rod ball joints worn
6) Relay rod ball joints worn
6) Steering relay lever bushes worn
7) Pins and/or bushes in spring shackles worn
8) Worn or incorrectly adjusted wheel bearings
9) Loose wheel nuts
10) Loose spring U-bolt nuts
11) Cracked spring mounts

There are probably a few more I have overlooked.
Good luck.

David

[patrolpaul]

no panhard on a leaf truck.

Would help if I read the first post properly

[mikesmith]

no worries guys

i have around 40, 42 psi in the tyres atm will let it down to 32.

i have looked over the front end. when the springover was done it was reverse shackled also so no steel bushes in the springs.

i will check the ball joints again and mayb i will put need rubbers in both end s of the springs as i have done the shackle bushes already.

thanks guys will let u know how i go.

[Wish I had coils]

I still have the shakes in my mk, I have swapped Idler arm (bit better) Other various tie rod ends.
The best thing was to adjust the king pins to the correct preload, made a big difference Still have the shakes but not as bad i'm taking the old girl into the tyre joint for an alignment hopfully fixs prob..

[DR Frankenstine]

From my experience with mq's your problem will be in the swivel hub bearings. though they may be tight enough with no movement in them they are probably worn. they get a grove in the cup where the bearing sitsin one position on straight corrugated roads. Change the bearings with the correct preload and get the tyres re-ballanced and get them to mark the truest running ones for the front. I guarentee this will fix your problem.

[bru21]

PSI is exactly that! If you run 35's they have probably double the footprint of the factory splitties. They need half the pressure to not bounce etc.